Pulldown device for well drills



Nov. 2, 1954 F. l.. SCOTT PuLLDowN DEVICE FoR WELL DRILLS Filed Sept. 13, 1948 ma@ KM FYOyGL. Sco# rr J inf'.

AT T ORAEY PULLDOWN DEVICE FOR WELL DRILLS Floyd L. Scott, Houston, Tex., assignor to Hughes Tool Company, Houston, Tex., a corporation of Delaware Application September 13, 1948, Serial No. 49,029

6 Claims. (Cl. Z55-22) This invention relates to improvements in pull-down devices for advancing the bit when drilling earth bores by the rotary method.

When drilling at shallow depths by the rotary method of drilling it is customary to provide a pull-down mechanism to exert a downward force on the kelly to provide sucient weight upon the bit, attached to the drill string therebelow, that effective drilling will be had. Mechanisms for providing a driving connection with the kelly have in the past been such as to provide a biting action upon the kelly, such as slips or a set screw type of connection or both. Such chucking arrangement causes rapid deterioration of the kelly, is relatively inconvenient to make up and break out, and is hence time consuming, and is unreliable in serving the purpose for which intended.

4 The present invention is intended, and it is an object of the invention to overcome diiiiculties to which reference has just been made.

Another object is to provide a pull-down mechanism having novel chucking means which is positive in action and which may be readily attached to or released from the kelly.

A further object is to provide a pull-down mechanism having parts which are movable to matching relation so that the pull-down assembly may move axially along the kelly but which, when moved to a nonmatching relation, effects inter-engagement with the kelly so that downward force. is transmitted from the pull-down mechanism to the kelly and thence to the drill string and bit attached thereto.

The foregoing are primary objects which, together with other objects and advantages of the invention, will be more fully apparent from the following description c onsidered in connection with the accompanying drawings in which:

Fig.l 1 is a sectional view through a pull-down structure embodying the invention, and is taken approximately on line 1-1 of Fig. 2;

Fig. 2 is a top plan view of the structure shown in Fi l;

i 3 is an enlarged detail showing the locking plate and the mechanism for holding such plate in operating position.

In the drawings showing an embodiment of the invention, the kelly is shown at 1, it being understood that such kelly is connected at its lower end to the drill string and bit (not shown) to be operated thereby. The kelly is non-circular, or angular in cross section, to pass slidably but non-rotatably through a non-circular opening 2 of substantially the same size and shape in the drive bushing or gear 3 which meshes with a pinion 4 driven by the shaft 5 which passes slidably but non-rotatably therethrough. This shaft is driven through bevel gears 6 from shaft 7 from a source of power (not shown) as well known in the art.

The pinion 4 and the gear 3 are mounted within a housing 10 secured to the pull-down cross arm 11 interconnecting conventional hydraulic feed cylinders, by Which force is applied as indicated by the arrow 12, so that such force is thence applied through the kelly 1 and the drill string to the bit. The bushing or gear 3 has an upward annular extension thereon passing out through the housing 10 and attached to the latching mechanism or chuck designated generally as 16. Such chuck comprises interconnected annular flange 17 and annulus 18 of which the former is threadably connected x 2,693,344 Patented Nov. 2, 1954 to the extension 15. The annulus 18 has an inwardly extending ange 23 whereby the members 17 `and 18 form a casing for the locking plate 20 which is thereby retained for angular movement relative to the remainder of the assembly to serve a purpose that will be further explained hereinafter.

It is to be noted that the locking plate 20 has a central opening 19 in alignment with and of substantially Vthe same size and shape as the opening 2 in the drive bushing or gear 3. Also, the kelly 1 has reduced cylindrical areas 21 at selected spaced intervals and of a diameter that the locking plate 20 may rotate thereabout. The nether surface of the locking plate 20 is, however, of a configuration to rest upon the shoulders 22 formed by the reduction on the kelly except when the locking plate is in such angular position that the kelly may pass axially through the pull-down assembly.

lt is apparent that the kelly may pass freely through the driving assembly when the opening 19 in the locking plate 20 and the opening 2 in the drive gear 3 are in matching relationship but that the locking plate 20 will ride upon the shoulder 22 when the openings are not in matching relationship. In the former case the assembly can, of course, move axially of the kelly and in the latter case the downward force applied to the cross arm or yoke 11 is transmitted by way of the locking plate to the shoulder 22 on the kelly. At the same time rotative eliort applied to the gear 3 will effect desired rotation of the kelly and the drill string attached thereto.

The locking plate 20 has upward extensions 25 attached at their upper ends to the inner ends of projections 24 of a brake drum 26. The peripheral surface of this drum may be engaged by the friction element 27 on the lever 28 mounted on the arm 29 on the housing 10. In this manner a force is exerted to resist rotation of the drum 26, and hence of the locking plate 20 secured thereto, when the drive bushing or gear 3 is rotated from power supplied through the drive shaft 5.

The locking plate 20 and the drum 26 are normally urged in a clock-wise direction relative to the remainder of the assembly by means of the spring 30 having one end anchored to the eye bolt 31 secured to the casing 16. The other end of the spring 30 is attached to an eye bolt 32 mounted on one of the inwardly extending projections 24 of the drum 26. The opposite end of the eye bolt 32 extends downwardly such a distance vthat it forms an abutment engageable by the stops or inwardly extending ears 33 and 34 on the ilange 23 of the annulus 18.

The operation of the mechanism thus far described is believed apparent from the description. By way of summary and further explanation of the invention, it will be assumed that the parts are in the relative positions indicated in the drawings in which case the locking plate 20 is in engagement with a shoulder 22 on the kelly 1. Continuous driving of the assembly through power applied to the shaft 5 and the exertion of a pulldown force upon the yoke 11 in the direction indicated by the arrow 12 effect desired advance of the bit.

If it is desired to engage the kelly 1 at a higher level for additional drilling the lever 28 may be manually fC e ice operated to apply a braking force to the drum 26 and hence to the locking plate 20. Such braking force resists rotation of the locking plate and hence overcomes the tension of the spring 30 whereby there will be relative movement between the locking plate 20 and the drive bushing 3 so that the stop on the lower end of the eye bolt 32 will engage abutment 34 and the openings 19 and 2, respectively, in these members will become aligned. Thereupon the entire driving assembly may be lifted relative to the kelly 1 and upon release of the lever 28 the locking plate 20 will rotate under the influence of the spring 30 until the abutment 33 engages the lower end of the eye bolt 32 whereby the locking plate engages the shoulder 22 at a reduced area on the kelly at a higher level, thereupon drilling may proceed as before.

In a similar manner the kelly and attached string, can be lifted step-by-step by releasing the chuck mechanism and then lowering the entire assembly for re-engagement with'a lower reduced area on the kelly 1. Then, upward movement of the assembly will cause the locking plate to engage the downwardly facing shoulder'on the kelly and effect lifting of the kelly and dr1ll string.

What is claimed is:

l.. A chuck for releasable connection with a kelly in a pull-down in rotary well drilling equipment comprising, a drive member, a locking member rotatively and coaxially mounted thereon, there being coaxial, noncircular openings of the same size and shape in said members, spaced stops on one of said members, means on the other member for engagement with said stops to limit relative rotation of the members to positions when the openings are in matching and nonmatching relationship respectively, and means normally holding said rst mentioned means in engagement with one stop with the openings in nonmatching relation.

2. In 'rotary well drilling equipment having a pulldown assembly for applying force axiallyy of a kelly having alternate non-circular and circular portions with shoulders therebetween, the improvement comprising, a drive bushing member rotatably mounted upon and movable with the pull-down assembly, a casing rigidly mounted on said bushing and having an inwardly extending portion, a locking plate member rotatably mounted in said casing, below said inwardly extending portion of the casing to move axially with the bushing, there being non-circular aligned openings of the same size and shape in the bushing and plate adapted to move into matching and nonmatching relation from relative rotation between the bushing and plate, a stop on one of said members, spaced abutments on the other of the members eugageable by said stop, means normally holding the bushing and plate in a relative position with the stop and one abutment in engagement and with the openings in nonmatching relation, and means for moving the plate relative vto the drive bushing member to bring the stop into engagement with the other of' said abutments and the openings in the bushing and plate into matching relation so that the kelly may pass axially therethrough.

3. Avwell drilling apparatus comprising, a drive member having a non-circular opening to slidably but nonrotatably receive a kelly having a cross section of sub'- stantially the same size and shape as the non-circular opening in the drive member and having a spaced cylindrical areas thereon, a casing mounted on and rotatable with said drive member, a locking plate rotatively mounted within said casing and coaxally of the drive member and having an opening of the same size and shape as the opening in the drive member to slidably pass the kelly when the openings are in matching relationship, and means for rotatively moving the plate member relative to the drive member to bring the openings into nonmatching rel-ation andfor normally holding the plate and member with their openings in Vsuch nonm-atching relation, whereby portions of the platev move into opposed relation to 'the shoulders formed 'by one of the cylindrical reduced areas on the kelly.

4. Well drilling apparatus comprising an assembly including, a cross arm, a bushing rotatably mounted thereon, a locking membercoaxially mounted on said bushing for limited rotational movement relative thereto, there being matching, coaxial, non-circular openings in said bushing and member, a polygonal kelly adapted to pass slidably but non-rotatively through said openings when they are positioned in matching relationship and having reduced Vcylindrical are'as with adjacent shoulders, and means normally holding said bushing and locking member with` the openings i'n nonm'atching lrelation whereby the locking member is engageable with one of said shoulders as the assembly is moved axially of the kelly.

5. Well drillingy apparatus comprising an assembly including, a cross arm, a bushing rotatably mounted thereon, a locking member coaxially mounted on said bushing for limited rotational movement relative thereto, there being r'natc'h'ing,y coaxial, non-circular openings in 'said bu'shin'g and member, a polygonal kelly adapted to pass slidably but non-rotatively through said openings when they are positioned in matching relationship and havin'g reduced cylindrical areas with adjacent shoulders, and additional means for producing relative movement between saidjmernbe'rs to bring the openings into matching relation for movement of 'the assembly axially of the kelly.

6. Well drilling apparatus including, a cross arm, a bushing rotatably mounted thereon, a locking member coaxially mounted von said bushing for limited rotational movement relative thereto, there being matching, 'coaxial, non-circular openings. in said bushing and member, a polygonal kelly adapted to pass slidably but nonrotatively through said openings when they are positioned in matching relationship and having reduced 'cylindrical areas with adjacent shoulders, means normally holding said bushing and locking member with the -openings in non-matching'relation, and means for restraining the locking member against rotation during continued rotation of the drive memberV to produce rel'ative movement between the bushing andlocking memberv to bring the 'openingsv into matchingv relation.

References Cited in the tile of this p'a'tent UNITED STATES PATENTS Number Y, Name D ate v 1,628,282 Sheldon May 10, 194217 1,682,955 Copeland Sept. L4, 1'92'8 l2,612,21810- .T-oh'ansen At'rg. 27, 1935 2,151,673 Acker Mar. 2s, 1'9'39 2,188,197 Caldwell et a1. Jan. 12'3., 1940 2,327,616 Abramson etal. Aug. v24, 1:9213 2,393,603 Beeth Jan. `29, 1-946 

